An alternative to modelling lithium transport in the electrode materials using a nonlinear diffusion equation is to use the Cahn–Hilliard reaction (CHR) theory that naturally captures the phase transformation [1]}, [2]}. The CHR model is a special case of the phase transformations model developed by Bazant [3]} based on non-equilibrium thermodynamics. It corresponds to rate limitation by diffusion and describes bulk phase separation driven by heterogeneous reactions localised on the surface and described by a flux matching boundary condition. In an arbitrary domain \(\Omega \)  it reads
\({c}{t} &= -\nabla \cdot \mathbf {F}, & \text{ in } \Omega ,\\-\mathbf {F} \cdot *{n} &= R \left( \left\lbrace  \frac{\delta G}{\delta c} \right\rbrace  \right), & \text{ at } \partial \Omega ,\) 
